Isotope techniques applied to groundwater movement in the Konya plain

As the yields of surface waters in the Konya plain decrease noticeably in the summer months the need arises for using groundwater reservoirs for irrigation in the region. To obtain maximum benefits from groundwater the characteristics of the groundwater must be known. Conventional hydrological methods were used to locate groundwater, but these proved inadequate for sufficiently exact conclusions to be drawn. The aim of these investigations was to determine the location of aquifers in the Konya plain by using the stable isotopes oxygen-18 and deuterium. Samples were taken every month at 35 sampling points scattered homogeneously throughout the region. In addition, precipitation samples were collected at three points in the recharge area. The stable isotope values of these samples indicated that two main water bodies with different characteristics existed (one at a shallow and the other at a deeper level), and that they were fed by precipitation of continental type. In the second step of the study an attempt was made to determine the transit time in the deep aquifer by using tritium, but it was not possible to make calculations because the tritium values were extremely low. (author)